Latest news with #globalWarming
CBC
26-05-2025
- Science
- CBC
Water temperature in the Gulf of St. Lawrence was the hottest ever recorded in 2024
Scientists who study the gulf are noticing worrisome trends as global temperatures rise. That can lead to dangerous conditions for marine life.
Asharq Al-Awsat
26-05-2025
- Science
- Asharq Al-Awsat
Sea Level Rise Expected to Accelerate
Rising seas will severely test humanity's resilience in the second half of the 21st century and beyond, even if nations defy the odds and cap global warming at the ambitious 1.5 degrees Celsius target, researchers said last week. The pace at which global oceans are rising has doubled in three decades, and on current trends will double again by 2100 to about one centimeter per year, they reported in a study. 'Limiting global warming to 1.5C would be a major achievement' and avoid many dire climate impacts, lead author Chris Stokes, a professor at Durham University in England, told AFP on Saturday. 'But even if this target is met,' he added, 'sea level rise is likely to accelerate to rates that are very difficult to adapt to.' Absent protective measures such as sea walls, an additional 20 centimeters (7.8 inches) of sea level rise—the width of a letter-size sheet of paper—by 2050 would cause some $1 trillion in flood damage annually in the world's 136 largest coastal cities, earlier research has shown. Some 230 million people live on land within one meter (3.2 feet) of sea level, and more than a billion reside within 10 meters. Sea level rise is driven in roughly equal measure by the disintegration of ice sheets and mountain glaciers, as well as the expansion of warming oceans, which absorb more than 90% of the excess heat due to climate change. Averaged across 20 years, Earth's surface temperature is currently 1.2C above pre-industrial levels, already enough to lift the ocean watermark by several meters over the coming centuries, Stokes and colleagues noted in the journal Communications Earth & Environment. The world is on track to see temperatures rise 2.7C above that benchmark by the end of the century. Tipping points In a review of scientific literature since the last major climate assessment by the UN-mandated Intergovernmental Panel on Climate Change (IPCC), Stokes and his team focused on the growing contribution of ice sheets to rising seas. In 2021, the IPCC projected 'likely' sea level rise of 40 to 80 centimeters by 2100, depending on how quickly humanity draws down greenhouse gas emissions, but left ice sheets out of their calculations due to uncertainty. The picture has become alarmingly more clear since then. 'We are probably heading for the higher numbers within that range, possibly higher,' said Stokes. Satellite data has revealed that ice sheets with enough frozen water to lift oceans some 65 meters are far more sensitive to climate change than previously suspected. The amount of ice melting or breaking off into the ocean from Greenland and West Antarctica, now averaging about 400 billion tons a year, has quadrupled over the last three decades, eclipsing runoff from mountain glaciers. 'We used to think that Greenland wouldn't do anything until the world warmed 3C,' said Stokes. 'Now the consensus for tipping points for Greenland and West Antarctica is about 1.5C.' 'If you want to slow sea level rise from ice sheets, you clearly have to cool back from present-day temperatures,' Stokes told AFP. 'To slow sea level rise from ice sheets to a manageable level requires a long-term temperature goal that is close to +1C, or possibly lower.'
CNA
20-05-2025
- Science
- CNA
Dire sea level rise likely even in a 1.5°C world: Study
PARIS: Rising seas will severely test humanity's resilience in the second half of the 21st century and beyond, even if nations defy the odds and cap global warming at the ambitious 1.5 degrees Celsius target, researchers said on Tuesday (May 20). The pace at which global oceans are rising has doubled in three decades, and on current trends will double again by 2100 to about one centimetre per year, they reported in a study. "Limiting global warming to 1.5°C would be a major achievement" and avoid many dire climate impacts, lead author Chris Stokes, a professor at Durham University in England, told AFP. "But even if this target is met," he added, "sea level rise is likely to accelerate to rates that are very difficult to adapt to." Absent protective measures such as sea walls, an additional 20cm of sea level rise - the width of a letter-size sheet of paper - by 2050 would cause some US$1 trillion in flood damage annually in the world's 136 largest coastal cities, earlier research has shown. Some 230 million people live on land within one metre of sea level, and more than a billion reside within 10m. Sea level rise is driven in roughly equal measure by the disintegration of ice sheets and mountain glaciers, as well as the expansion of warming oceans, which absorb more than 90 per cent of the excess heat due to climate change. Averaged across 20 years, Earth's surface temperature is currently 1.2°C above pre-industrial levels, already enough to lift the ocean watermark by several metres over the coming centuries, Stokes and colleagues noted in the journal Communications Earth & Environment. The world is on track to see temperatures rise 2.7°C above that benchmark by the end of the century. TIPPING POINTS In a review of scientific literature since the last major climate assessment by the UN-mandated Intergovernmental Panel on Climate Change (IPCC), Stokes and his team focused on the growing contribution of ice sheets to rising seas. In 2021, the IPCC projected "likely" sea level rise of 40 to 80 centimetres by 2100, depending on how how quickly humanity draws down greenhouse gas emissions, but left ice sheets out of their calculations due to uncertainty. The picture has become alarmingly more clear since then. "We are probably heading for the higher numbers within that range, possibly higher," said Stokes. The scientist and his team looked at three baskets of evidence, starting with what has been observed and measured to date. Satellite data has revealed that ice sheets with enough frozen water to lift oceans some 65m are far more sensitive to climate change than previously suspected. The amount of ice melting or breaking off into the ocean from Greenland and West Antarctica, now averaging about 400 billion tonnes a year, has quadrupled over the last three decades, eclipsing runoff from mountain glaciers. Estimates of how much global warming it would take to push dwindling ice sheets past a point of no return, known as tipping points, have also shifted. "We used to think that Greenland wouldn't do anything until the world warmed 3°C," said Stokes. "Now the consensus for tipping points for Greenland and West Antarctica is about 1.5°C." The 2015 Paris climate treaty calls for capping global warming at "well below" 2°C, and 1.5°C if possible. The scientists also looked at fresh evidence from the three most recent periods in Earth's history with comparable temperatures and atmospheric levels of CO2, the main driver of global warming. About 125,000 years ago during the previous "interglacial" between ice ages, sea levels were two to nine metres higher than today despite a slightly lower average global temperature and significantly less CO2 in the air - 287 parts per million, compared to 424 ppm today. A slightly warmer period 400,000 ago with CO2 concentrations at about 286 ppm saw oceans 6-to-13 metres higher. And if we go back to the last moment in Earth's history with CO2 levels like today, some three million years ago, sea levels were 10-to-20 metres higher. Finally, scientists reviewed recent projections of how ice sheets will behave in the future. "If you want to slow sea level rise from ice sheets, you clearly have to cool back from present-day temperatures," Stokes told AFP.
News.com.au
20-05-2025
- Science
- News.com.au
Dire sea level rise likely even in a 1.5C world: study
Rising seas will severely test humanity's resilience in the second half of the 21st century and beyond, even if nations defy the odds and cap global warming at the ambitious 1.5 degrees Celsius target, researchers said Tuesday. The pace at which global oceans are rising has doubled in three decades, and on current trends will double again by 2100 to about one centimetre per year, they reported in a study. "Limiting global warming to 1.5C would be a major achievement" and avoid many dire climate impacts, lead author Chris Stokes, a professor at Durham University in England, told AFP. "But even if this target is met," he added, "sea level rise is likely to accelerate to rates that are very difficult to adapt to." Absent protective measures such as sea walls, an additional 20 centimetres (7.8 inches) of sea level rise -- the width of a letter-size sheet of paper -- by 2050 would cause some $1 trillion in flood damage annually in the world's 136 largest coastal cities, earlier research has shown. Some 230 million people live on land within one metre (3.2 feet) of sea level, and more than a billion reside within 10 metres. Sea level rise is driven in roughly equal measure by the disintegration of ice sheets and mountain glaciers, as well as the expansion of warming oceans, which absorb more than 90 percent of the excess heat due to climate change. Averaged across 20 years, Earth's surface temperature is currently 1.2C above pre-industrial levels, already enough to lift the ocean watermark by several metres over the coming centuries, Stokes and colleagues noted in the journal Communications Earth & Environment. The world is on track to see temperatures rise 2.7C above that benchmark by the end of the century. - Tipping points - In a review of scientific literature since the last major climate assessment by the UN-mandated Intergovernmental Panel on Climate Change (IPCC), Stokes and his team focused on the growing contribution of ice sheets to rising seas. In 2021, the IPCC projected "likely" sea level rise of 40 to 80 centimetres by 2100, depending on how how quickly humanity draws down greenhouse gas emissions, but left ice sheets out of their calculations due to uncertainty. The picture has become alarmingly more clear since then. "We are probably heading for the higher numbers within that range, possibly higher," said Stokes. The scientist and his team looked at three baskets of evidence, starting with what has been observed and measured to date. Satellite data has revealed that ice sheets with enough frozen water to lift oceans some 65 metres are far more sensitive to climate change than previously suspected. The amount of ice melting or breaking off into the ocean from Greenland and West Antarctica, now averaging about 400 billion tonnes a year, has quadrupled over the last three decades, eclipsing runoff from mountain glaciers. Estimates of how much global warming it would take to push dwindling ice sheets past a point of no return, known as tipping points, have also shifted. "We used to think that Greenland wouldn't do anything until the world warmed 3C," said Stokes. "Now the consensus for tipping points for Greenland and West Antarctica is about 1.5C." The 2015 Paris climate treaty calls for capping global warming at "well below" 2C, and 1.5C if possible. The scientists also looked at fresh evidence from the three most recent periods in Earth's history with comparable temperatures and atmospheric levels of CO2, the main driver of global warming. About 125,000 years ago during the previous "interglacial" between ice ages, sea levels were two to nine metres higher than today despite a slightly lower average global temperature and significantly less CO2 in the air -- 287 parts per million, compared to 424 ppm today. A slightly warmer period 400,000 ago with CO2 concentrations at about 286 ppm saw oceans 6-to-13 metres higher. And if we go back to the last moment in Earth's history with CO2 levels like today, some three million years ago, sea levels were 10-to-20 metres higher. Finally, scientists reviewed recent projections of how ice sheets will behave in the future. "If you want to slow sea level rise from ice sheets, you clearly have to cool back from present-day temperatures," Stokes told AFP.
BBC News
20-05-2025
- Science
- BBC News
Coastlines in danger even if climate target met, scientists warn
The world could see hugely damaging sea-level rise of several meters or more over the coming centuries even if the ambitious target of limiting global warming to 1.5C is met, scientists have 200 countries have pledged to try to keep the planet's warming to 1.5C, but the researchers warn that this should not be considered "safe" for coastal drew their conclusion after reviewing the most recent studies of how the ice sheets are changing - and how they have changed in the the scientists stress that every fraction of a degree of warming that can be avoided would still greatly limit the risks. The world's current trajectory puts the planet on course for nearly 3C of warming by the end of the century, compared with the late 1800s, before humans began burning large amounts of planet-heating fossil fuels. That's based on current government policies to reduce carbon emissions from fossil fuels and other polluting even keeping to 1.5C would still lead to continued melting of Greenland and Antarctica, as temperature changes can take centuries to have their full impact on such large masses of ice, the researchers say."Our key message is that limiting warming to 1.5C would be a major achievement - it should absolutely be our target - but in no sense will it slow or stop sea-level rise and melting ice sheets," said lead author Prof Chris Stokes, a glaciologist at Durham 2015 Paris climate agreement saw the world's nations agree to keep global temperature rises "well below" 2C - and ideally has often been oversimplified to mean 1.5C is "safe", something glaciologists have cautioned against for authors of the new paper, published in the journal Communications Earth and Environment, draw together three main strands of evidence to underline this case. First, records of the Earth's distant past suggest significant melting – with sea levels several metres higher than present - during previous similarly warm periods, such as 125,000 years the last time there was as much planet-warming carbon dioxide in the atmosphere as today - about 3 million years ago - sea levels were about 10-20m current observations already show an increasing rate of melting, albeit with variation from year to year. "Pretty dramatic things [are] happening in both west Antarctica and Greenland," said co-author Prof Jonathan Bamber, director of the Bristol Glaciology Antarctica appears, for now at least, more stable. "We're starting to see some of those worst case scenarios play out almost in front of us," added Prof scientists use computer models to simulate how ice sheets may respond to future climate. The picture they paint isn't good."Very, very few of the models actually show sea-level rise slowing down [if warming stabilises at 1.5C], and they certainly don't show sea-level rise stopping," said Prof major concern is that melting could accelerate further beyond "tipping points" due to warming caused by humans - though it's not clear exactly how these mechanisms work, and where these thresholds sit. "The strength of this study is that they use multiple lines of evidence to show that our climate is in a similar state to when several metres of ice was melted in the past," said Prof Andy Shepherd, a glaciologist at Northumbria University, who was not involved in the new publication."This would have devastating impacts on coastal communities," he estimated 230 million people live within one metre of current high tide a "safe" limit of warming is inherently challenging, because some populations are more vulnerable than if sea-level rise reaches a centimetre a year or more by the end of the century - mainly because of ice melt and warming oceans - that could stretch even rich countries' abilities to cope, the researchers say."If you get to that level, then it becomes extremely challenging for any kind of adaptation strategies, and you're going to see massive land migration on scales that we've never witnessed [in modern civilisation]," argued Prof this bleak picture is not a reason to stop trying, they say."The more rapid the warming, you'll see more ice being lost [and] a higher rate of sea-level rise much more quickly," said Prof Stokes."Every fraction of a degree really matters for ice sheets." Additional reporting by Phil Leake Sign up for our Future Earth newsletter to keep up with the latest climate and environment stories with the BBC's Justin Rowlatt. Outside the UK? Sign up to our international newsletter here.
